Candida albicans is an opportunistic pathogen that is responsible for mucosal and dermal infections (candidiasis) as well as disseminated infection and death in systemically predisposed patients. Oral candidiasis is initiated by candidal adherence to host tissues and in the presence of salivary dysfunction this often results in chronic oral infection. The study of saliva in relation to candidal adherence may provide insight into the ecologic determinants surrounding candidal colonization and create new approaches to the treatment of oral as well as disseminated infections. This plan will be implemented in two phases with four specific aims. In Phase I, specific aims 1 and 2 will be directed at comparing mucosal and candidal pellicles in normal subjects and normal subjects carrying C.albicans (populations IA and IB, respectively) and salivary dysfunction patients secondary to Sjogren's disease and post-head and neck irradiation therapy (population IIA and IIB, respectively). In this section salivary components extracted from buccal epithelial cells (BEC) harvested in vivo will be identified by indirect immunofluorescence, immuno-dot blotting and quantitation of mucosal pellicle components will be carried out using immuno-dot blotting coupled with scanning laser densitometry. In Phase II, the nature of candida-salivary interactions will be studied. In specific aim 3, the effects of normal parotid and submandibular-sublingual salivas as well as purified salivary components on the adherence of Candida albicans (isolated from populations I and II) to buccal epithelial cells will be examined. This will be accomplished by using an in vitro adherence assay utilizing radiolabeled C. albicans. In specific aim 4 the mechanism of interaction(s) between the salivary constituents of candidal pellicle (identified in phase I) and C. albicans surface components will be studied. This will be accomplished using purified salivary components derivatized with iodinated reversible photoaffinity crosslinking agents.